Differential regulation of urokinase-type-1 inhibitor complex endocytosis by phorbol esters in different cell lines is associated with differential regulation of alpha 2-macroglobulin receptor and urokinase receptor expression.
Mol Cell Endocrinol
; 109(2): 209-17, 1995 Apr 01.
Article
en En
| MEDLINE
| ID: mdl-7664984
Complex between urokinase and its type-1 inhibitor (uPA-PAI-1) may, when bound to the urokinase receptor (uPAR), be endocytosed by an ensuing binding of the complex to the multiligand receptors alpha (2)-macroglobulin receptor/low density lipoprotein receptor-related protein (alpha 2MR/LRP) and glycoprotein 330 (gp330). We have found that phorbol esters regulate endocytosis of uPA-PAI-1 differently in different cell lines. In COS-1 cells, expressing uPAR and high levels of alpha 2MR/LRP under basal conditions, phorbol esters cause a time-dependent decrease in endocytosis concomitantly with a parallel down-regulation of alpha 2MR/LRP expression. An up-regulation of uPAR expression was also observed. General endocytosis via the clathrin-coated pit pathway was not affected by PMA treatment, as judged from measurements of transferrin endocytosis. In LLC-PK1 cells, expressing alpha 2MR/LRP but not uPAR under basal conditions, phorbol esters transiently increase endocytosis in parallel with a transient induction of uPAR expression, while there was virtually no change in alpha 2MR/LRP expression. Differential regulation of endocytosis therefore seems to be caused by differential regulation of the receptors, with either the alpha 2MR/LRP-level (in COS)-1 cells) or the uPAR-level (in LLC-PK1 cells) being rate-limiting.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Acetato de Tetradecanoilforbol
/
Activador de Plasminógeno de Tipo Uroquinasa
/
Inhibidor 1 de Activador Plasminogénico
/
Receptores de Superficie Celular
/
Endocitosis
Tipo de estudio:
Risk_factors_studies
Límite:
Animals
/
Humans
Idioma:
En
Revista:
Mol Cell Endocrinol
Año:
1995
Tipo del documento:
Article
País de afiliación:
Dinamarca
Pais de publicación:
Irlanda